The Moen 3838 Four Function Standard Shower Head is a wonderful shower head that has four different spray options massage, fine, full, and combined (massage & full). The outer ring is used to select the function you desire. The Moen 3838 Four Function Standard shower head has a maximum flow rating of 2.5 gpm (9.5 L/min) at 80 psi. This great shower head has also been third party certified to meet ASME A112.18.1/ CSA B125.1 and all applicable requirements referenced therein. The Moen 3838 Four Function Standard shower head is backed by a limited lifetime manufacturer warranty against leaks, drip and finish defects when used in residential applications, and a five year warranty when used in commercial applications.